Stroke prevention in atrial fibrillation: an update on current management strategies.

Stroke attributed to atrial fibrillation (AF) confers significant morbidity and mortality. In the past, warfarin has been the only successful stroke prevention agent available. However, it is often underutilized due to its well-known limitations, leaving many patients without adequate stroke protection. The last decade has seen significant strides forward in the field of anticoagulation for AF. The development of several novel oral anticoagulants that have superior efficacy, improved safety profile and fixed doses without the need for regular monitoring make them favorable as viable alternatives to warfarin. Improved risk scoring systems for both thromboembolism and bleeding have also allowed clinicians to better target patients most likely to benefit from these new therapies. In addition, non-pharmacological approaches to stroke prevention such as left atrial appendage exclusion devices may be useful in patients whom anticoagulation therapy is contraindicated. These new pharmacological and non-pharmacological options for stroke prevention in AF permit clinicians to tailor their management of patients according to individual needs and characteristics. The present review aims to outline the latest up-to-date management of AF in stroke prevention.

Tissue Doppler echocardiography.

Tissue Doppler echocardiography, since its introduction more than 2 decades ago, had revolutionized echocardiography. In the quest to directly quantify myocardial function, increase sensitivity to detect early subtle myocardial dysfunction and improve ease of use, tissue Doppler echocardiography has evolved from pulsed wave tissue Doppler, to color-coded tissue Doppler and to 2-dimensional (2D) speckle tracking, and from myocardial velocity to strain/strain rate imaging. Over the years, numerous studies have demonstrated the value of tissue Doppler echocardiography in the diagnosis and risk stratification of a wide range of cardiac diseases. However, each generational change in tissue Doppler echocardiography involves technological software advancements that are not directly comparable to previous generations. To extensively present the technical differences between tissue Doppler imaging and speckle tracking analyses, and to review the clinical implications of myocardial velocity, strain and strain rate imaging by tissue Doppler versus speckle tracking, is well beyond the scope of the present article. Thus, the aim of the present review is to focus on tissue Doppler imaging, from basic physical principles and technical limitations, to differences in myocardial velocity, strain and strain rate imaging in healthy and diseased states, and finally the prognostic value of tissue Doppler deformation imaging in predicting adverse cardiac outcomes.

Advanced applications of 3-dimensional echocardiography.

Over the last few decades, advancements in ultrasound, electronic and computing technologies have permitted current second generation 3-dimensional (3D) echocardiography to display on-line 3D rendered images of the heart. Since various studies demonstrated its superiority over 2-dimensional echocardiography, there is growing enthusiasm to embrace this new 3D echocardiographic technology. With its increasing widespread clinical availability, 3D echocardiography is getting closer to routine clinical use. However, as with any new emerging technologies, clinical applications of 3D echocardiography should be based on current evidence. This review will focus on the evidence from clinical studies that form the scientific basis for the advanced applications of 3D echocardiography, from cardiac chamber volume assessments, left ventricular dyssynchrony assessments, quantifications of valvular abnormalities, to the role of 3D echocardiography during cardiac interventions.